Harry Potter author J.K. Rowling and her husband Neil Murray have announced the name of their new baby girl: Mackenzie Jean Rowling Murray.
"Neil and I are absolutely delighted to say that our new daughter arrived on Sunday evening," Rowling says in a statement on her Web site. "Her name is Mackenzie Murray (middle names Jean Rowling) and she is ridiculously beautiful, though I suppose I might be biased."
The new mom adds: "Thank you all so very much for your kind congratulations on various fan sites, they mean more than you can know. I was planning to do a few more updates to this site when events overtook me on Sunday, so when I've got past the next feed or two, and maybe caught up on a little sleep, I shall make a few more tweaks. In the meantime, I hope you're all having as good a week as I am!"
As for the origin of Mackenzie, "It's just a name that they like," Rowling's spokesman Mark Hutchinson tells PEOPLE.
Mackenzie Jean was born Jan. 23 in Edinburgh. Rowling and her husband also have a son David, who turns 2 in March. Rowling, who turns 40 in July, also has an 11-year-old daughter Jessica from a previous marriage.
Meanwhile, Rowling's sixth installment in the young wizard series, Harry Potter and the Half-Blood Prince, is due to be published on July 16.